1 Field of the Invention
This invention relates to motorized wheelchairs and, more particularly, to wheelchair-mounted control systems for enabling disabled persons to control operations of a motorized wheelchair, etc. with any movable portion of their body that enables them to put exposed skin into momentary contact with contact elements.
2. Description of the Prior Art
Motorized wheelchairs have been a boon to disabled people. However, for persons who are substantially paralyzed from the neck down, very much weakened or who are quadriplegic, the problem of operating or controlling the motorized wheelchair (or other necessary functions) is formidable. Generally, such persons must have a constant attendant and, because of economics and other practical considerations, the ability of such persons to have any degree of independence and make any contribution to society has been severely limited.
Various mechanisms have been proposed for permitting a quadriplegic to attain some degree of control over movement of a motorized wheelchair. For example, U.S. Pat. No. 3,374,845 of Selwyn provides a head-mounted servo-control system in which the handicapped individual, by a selective movement of his head, can command the operation of a motorized wheelchair. The system disclosed in that patent uses a head-mounted unit, in the form of a helmet or eyeglass frame, containing a position sensing assembly for responding to the different directions of movement of the user's head. Unfortunately, the system disclosed in the Selwyn patent is quite complex and would be very expensive to put into practice. As a result of its complexity, it would also tend to suffer from the maintenance and repair problems naturally associated with complex systems. It seems apparent that to the disabled individual, reliability is the paramount characteristic of any prosthetic or other device he utilizes. However, although cost may be of secondary importance, it is still a significant factor in bringing to the many disabled persons in our society the benefits of modern technology.
Other wheelchair control systems utilize the user's eye movement or reflectivity of the user's eye to effect control and operation; however, such systems are very sensitive to ambient lighting conditions, a strong light often causing the system to "run away". Still other wheelchair control systems employ breath-operated pressure switches or tongue-operated toggle switches; however, such apparatus often require more strength on the part of the user that he can exert.
For these and other reasons, a need still exists for a wheelchair control system which a user, having substantially no strength, can operate.